From f75d712cb569543400bbb22487d73f9ace0027eb Mon Sep 17 00:00:00 2001 From: Bharath Rupireddy Date: Mon, 21 Mar 2022 05:45:07 +0000 Subject: [PATCH v6] Add checkpoint stats of snapshot and mapping files of pg_logical dir At times, there can be many snapshot and mapping files under pg_logical dir that the checkpoint might have to delete/fsync based on the cutoff LSN which can increase the checkpoint time. Add stats related to these files to better understand the delays or time spent by the checkpointer processing them. Add these new log message only when necessary i.e. at least one snapshot or mapping files is processed during the checkpoint. --- src/backend/access/heap/rewriteheap.c | 6 ++++ src/backend/access/transam/xlog.c | 37 +++++++++++++++++++++ src/backend/replication/logical/snapbuild.c | 4 +++ src/include/access/xlog.h | 13 ++++++++ 4 files changed, 60 insertions(+) diff --git a/src/backend/access/heap/rewriteheap.c b/src/backend/access/heap/rewriteheap.c index 2a53826736..59cc3fa567 100644 --- a/src/backend/access/heap/rewriteheap.c +++ b/src/backend/access/heap/rewriteheap.c @@ -1210,6 +1210,8 @@ CheckPointLogicalRewriteHeap(void) if (cutoff != InvalidXLogRecPtr && redo < cutoff) cutoff = redo; + CheckpointStats.repl_map_cutoff_lsn = cutoff; + mappings_dir = AllocateDir("pg_logical/mappings"); while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL) { @@ -1247,6 +1249,8 @@ CheckPointLogicalRewriteHeap(void) ereport(ERROR, (errcode_for_file_access(), errmsg("could not remove file \"%s\": %m", path))); + + CheckpointStats.repl_map_files_rmvd_cnt++; } else { @@ -1280,6 +1284,8 @@ CheckPointLogicalRewriteHeap(void) (errcode_for_file_access(), errmsg("could not close file \"%s\": %m", path))); } + + CheckpointStats.repl_map_files_syncd_cnt++; } FreeDir(mappings_dir); diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index b5a6e0cd61..5b752de46e 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -6157,6 +6157,36 @@ LogCheckpointEnd(bool restartpoint) (int) (PrevCheckPointDistance / 1024.0), (int) (CheckPointDistanceEstimate / 1024.0)); + if (CheckpointStats.repl_snap_files_rmvd_cnt > 0) + { + long t_msecs; + + t_msecs = TimestampDifferenceMilliseconds(CheckpointStats.repl_snap_start_t, + CheckpointStats.repl_snap_end_t); + + appendStringInfo(&logmsg, + _("; logical decoding snapshot file(s) removed=%lu, time=%ld.%03d s, cutoff LSN=%X/%X"), + CheckpointStats.repl_snap_files_rmvd_cnt, + t_msecs / 1000, (int) (t_msecs % 1000), + LSN_FORMAT_ARGS(CheckpointStats.repl_snap_cutoff_lsn)); + } + + if (CheckpointStats.repl_map_files_rmvd_cnt || + CheckpointStats.repl_map_files_syncd_cnt > 0) + { + long t_msecs; + + t_msecs = TimestampDifferenceMilliseconds(CheckpointStats.repl_snap_start_t, + CheckpointStats.repl_snap_end_t); + + appendStringInfo(&logmsg, + _("; logical decoding rewrite mapping file(s) removed=%lu, synced=%lu, time=%ld.%03d s, cutoff LSN=%X/%X"), + CheckpointStats.repl_map_files_rmvd_cnt, + CheckpointStats.repl_map_files_syncd_cnt, + t_msecs / 1000, (int) (t_msecs % 1000), + LSN_FORMAT_ARGS(CheckpointStats.repl_map_cutoff_lsn)); + } + ereport(LOG, errmsg_internal("%s", logmsg.data)); pfree(logmsg.data); } @@ -6815,8 +6845,15 @@ CheckPointGuts(XLogRecPtr checkPointRedo, int flags) { CheckPointRelationMap(); CheckPointReplicationSlots(); + + CheckpointStats.repl_snap_start_t = GetCurrentTimestamp(); CheckPointSnapBuild(); + CheckpointStats.repl_snap_end_t = GetCurrentTimestamp(); + + CheckpointStats.repl_map_start_t = GetCurrentTimestamp(); CheckPointLogicalRewriteHeap(); + CheckpointStats.repl_map_end_t = GetCurrentTimestamp(); + CheckPointReplicationOrigin(); /* Write out all dirty data in SLRUs and the main buffer pool */ diff --git a/src/backend/replication/logical/snapbuild.c b/src/backend/replication/logical/snapbuild.c index 83fca8a77d..e652acfbe6 100644 --- a/src/backend/replication/logical/snapbuild.c +++ b/src/backend/replication/logical/snapbuild.c @@ -1941,6 +1941,8 @@ CheckPointSnapBuild(void) if (redo < cutoff) cutoff = redo; + CheckpointStats.repl_snap_cutoff_lsn = cutoff; + snap_dir = AllocateDir("pg_logical/snapshots"); while ((snap_de = ReadDir(snap_dir, "pg_logical/snapshots")) != NULL) { @@ -1997,6 +1999,8 @@ CheckPointSnapBuild(void) path))); continue; } + + CheckpointStats.repl_snap_files_rmvd_cnt++; } } FreeDir(snap_dir); diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h index 09f6464331..32f8116388 100644 --- a/src/include/access/xlog.h +++ b/src/include/access/xlog.h @@ -172,6 +172,19 @@ typedef struct CheckpointStatsData * times, which is not necessarily the * same as the total elapsed time for the * entire sync phase. */ + + /* Statistics of snapshot files under "pg_logical/snapshots" */ + uint64 repl_snap_files_rmvd_cnt; + XLogRecPtr repl_snap_cutoff_lsn; + TimestampTz repl_snap_start_t; + TimestampTz repl_snap_end_t; + + /* Statistics of map files under "pg_logical/mappings" */ + uint64 repl_map_files_syncd_cnt; + uint64 repl_map_files_rmvd_cnt; + XLogRecPtr repl_map_cutoff_lsn; + TimestampTz repl_map_start_t; + TimestampTz repl_map_end_t; } CheckpointStatsData; extern CheckpointStatsData CheckpointStats; -- 2.25.1